<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0px;
            padding: 0px;
        }
        #top {
            width: 1000px;
            height: 100px;
            background-color: salmon;
            /* 居中对齐  距离上下边缘  左右*/
            margin: 0px auto;
        }
        #nav {
            width: 1000px;
            height: 50px;
            background-color: aquamarine;
            /* 居中对齐  距离上下边缘  auto 居中*/
            margin: 30px auto;
        }
        li {
            width: 100px;
            height: 50px;
            /* 去掉小圆点 */
            list-style: none;
            /* 横排序 */
            float: left;
            line-height: 50px;
            /* 水平方向居中对齐 */
            text-align: center;
        }
        li:hover {
            background-color: brown;
        }
        #main {
            width: 1000px;
            height: 300px;
            background-color:red;
            /* auto 居中对齐 */
            margin: 20px auto;
            /* 边框线 */
            border: 2px solid #FFC;
            /* 弧度 */
            border-radius: 40px 29px;
        } 
    </style>
</head>
<body>
    <div id="top">
        
        <img src="./素材/2.gif" height="100px" >
    </div>
    <div id="nav">
        <!-- 导航条 -->
        <ul>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
            <li>首页</li>
        </ul>
    </div>
    <div id="main">

    </div>
</body>
</html>